The present invention relates to a printing method for an inkjet printer containing a substantially closed ink duct provided with a nozzle, said duct being operationally connected to an electro-mechanical transducer, said method comprising determining whether an air bubble is present in the duct and subsequently eliminating the air bubble. The invention also relates to an inkjet printer which utilizes the present method.
A method of this kind is known from European patent application 1 013 453. In such an inkjet printer, the presence of an air bubble in the ink duct is determined by the application of a piezo-electric transducer used as a sensor. Due to the fact that such an air bubble may adversely affect the ejection of an ink drop from the duct nozzle (the drop formation process), attempts have been made to eliminate air bubbles from the duct. To do this, various methods have been suggested in the prior art, such as flushing the duct with new ink or interrupting the printing process to allow the air bubbles to dissolve in the ink. A disadvantage of the first suggested method is that it involves a relatively high loss of ink. A disadvantage of the second suggested method is that it requires a relatively long period of time, i.e., up to several minutes, depending on the size of the air bubble, thereby requiring the printing process to be interrupted for long time periods.